New York, NY, USA, 31 August 2016 | Darren Walton/AAP

Sam Stosur is on guard for a US Open ambush after surviving an early scare to move into the second round in New York for an eighth time.

Australia’s 2011 champion overcame three service breaks and some relentless pressure from free-hitting Italian Camila Giorgi to emerge with a 7-5 6-7(4) 6-1 victory on Tuesday.

Giorgi threw caution to the wind in pursuit of an Open boilover, clubbing 34 winners, but ultimately came unstuck with 45 unforced errors and 14 double-faults.

“It was really important for me to hold my ground and stay strong and really whenever I had my chance and an opportunity to take advantage of that,” Stosur said.

“So it’s really pleasing that I was able to do that the whole match and even after the disappointment of losing the tiebreak to start the third strong and get a bit of a lead.

“Then things started going in my favour.”

Seeded 16th this year, Stosur next plays Zhang Shuai, a friend and foe who crushed Australian wildcard Ellen Perez 6-1 6-1 in her opening match.

As she did at the French Open, Stosur is playing doubles with Zhang in New York after striking up a friendship with the Chinese through Australian coaching connections.

The two also clashed in the second round in Paris, with Stosur winning in straight sets.

But the Aussie favourite knows not to underestimate Zhang after the 27-year-old famously stormed to the quarterfinals of the Australian Open in January after losing her first 14 Grand Slam matches.

“She thought she was going to quit and all of a sudden let things go and played (on) and played great and it was certainly the story of the Aussie Open,” Stosur said.

“I was really happy for her when she won one in that first round and then she was able to continue and keep going.

“We know each other pretty well. She’s really got nothing to lose when she plays against me. I know that and she knows that and we both know each other’s games very well.

“So it’s a matter of who’s going to know all these things and put everything into play better on Thursday.

“But it’s not easy to play someone (like that), especially this year when she’s obviously having the best year she’s had on tour for quite some time and she’s feeling very confident.”